A clinical study of 23 cases of cerebral aneurysms associated with arteriovenous malformation

Etiology of cerebral aneurysms

Abstract

Cerebral aneurysms associated with arteriovenous malformation (AVM) have often been reported with special reference to the hemodynamic effect of aneurysm formation. We think that many factors including hemodynamic stress play important roles in the etiology of cerebral aneurysms associated with AVM and that all cases should not be discussed under a single mechanism. Therefore in this study we surveyed 23 AVMs with aneurysms and classified these cases by the relation between the aneurysm and the AVM and discussed the clinical characteristics of cases in each group. We summarized them as follows.
1) Group A : Those cases which had cerebral aneurysms located on the feeder of AVM. These patients were older than the other patients and it was suspected that arteriosclerosis was important in the formation of these aneurysms. These AVMs were no larger than AVMs without aneurysm. In those patients, rupture of aneurysm was a major hazard. 2) Group B : Those cases which had aneurysms located on the proximal arteries which were on the same side of AVM. The size of these AVMs tended to be slightly larger than those AVMs without aneurysm and the patients in this group were low risk as far as cerebral bleeding was concerned. 3) Group C : Those cases which had aneurysms which were thought to have no relation with AVM and the combination of the two lesions was thought to be coincidental. In these patients intracranial hemorrhage accounted for almost all the bleeding and the rupture of aneurysms was rare.